Semiconductor reaction chamber showerhead

ABSTRACT

A showerhead including a body having an opening, a first plate positioned within the opening and having a plurality of slots, a second plate positioned within the opening and having a plurality of slots, and wherein each of the first plate plurality of slots are concentrically aligned with the second plate plurality of slots.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional of, and claims priority to and thebenefit of, U.S. patent application Ser. No. 13/651,144, filed Oct. 12,2012 and entitled “SEMICONDUCTOR REACTION CHAMBER SHOWERHEAD,” which ishereby incorporated by reference herein.

FIELD OF THE DISCLOSURE

This disclosure relates generally to semiconductor processing, and moreparticularly to an apparatus and method for providing a processing gasto a substrate or wafer in a reaction chamber.

BACKGROUND

Semiconductor fabrication processes are typically conducted with thesubstrates supported within a chamber under controlled conditions. Formany purposes, semiconductor substrates (e.g., wafers) are heated insidethe process chamber. For example, substrates can be heated by directphysical contact with an internally heated wafer holder or “chuck.”“Susceptors” are wafer supports used in systems where the wafer andsusceptors absorb heat.

Some of the important controlled conditions for processing include, butare not limited to, pressure of the chamber, fluid flow rate into thechamber, temperature of the reaction chamber, temperature of the fluidflowing into the reaction chamber, and wafer position on the susceptorduring wafer loading.

Heating within the reaction chamber can occur in a number of ways,including lamp banks or arrays positioned above the substrate surfacefor directly heating the susceptor or susceptor heaters/pedestal heaterspositioned below the susceptor. Traditionally, the pedestal style heaterextends into the chamber through a bottom wall and the susceptor ismounted on a top surface of the heater. The heater may include aresistive heating element enclosed within the heater to provideconductive heat and increase the susceptor temperature.

Consistent processing and consistent results generally require carefulcontrol and metering of processing gases in the system. One of the lastresorts for controlling the processing gas is at the showerhead wherethe processing gas then contacts the wafer in the reaction chamber.Further, obtaining optimal flow rates and uniformity may be difficult attimes due to showerhead holes becoming clogged or parasitic precursorreactions occurring within the showerhead.

SUMMARY

Various aspects and implementations are disclosed herein that relate toreaction chamber showerhead designs and methods of providing aprocessing gas to a wafer. In one aspect, a showerhead includes a bodyhaving an opening, a first plate positioned within the opening andhaving a plurality of slots, a second plate positioned within theopening and having a plurality of slots, and wherein each of the firstplate plurality of slots are concentrically aligned with the secondplate plurality of slots.

In one implementation, the first plate slots may extend towards thesecond plate slots. The first plate slots may extend to a bottom surfaceof the second plate slots. The first and second plate slots may beoriented in a plurality of rings, wherein adjacent rings are offset withrespect to one another. The first and second plate plurality of slotsmay be oriented in a plurality of rings, wherein every other ring is inalignment. A gap may be formed between each of the plurality of firstslots and each of the plurality of second slots, and wherein the gapvaries between 0.575 mm and 0.800 mm. A gap may be formed within each ofthe plurality of first slots, and wherein the gap varies between 0.636mm and 1.100 mm.

In another implementation, a first gas flow cavity may be formed betweenthe body and the first plate and a second gas flow cavity may be formedbetween the first plate and the second plate. The first gas flow cavitymay convey a first gas and wherein the second gas flow cavity may conveya second gas. The first gas cavity may further include a purge channelseparate from a first gas flow inlet. The purge channel may bepositioned at a perimeter of the first cavity. The purge channel mayprovide additional purge gas flow during a purging operation. The purgechannel may be operatively connected to an exhaust. The purge channelmay remove the first gas during a purging operation. The second gascavity may further include a purge channel separate from the second gasflow inlet and wherein the purge channel may provide a gas flow or avacuum.

In yet another implementation, a plurality of apertures may extend froma top surface to a bottom surface of the first plate and are separatefrom the first plate plurality of slots. The plurality of apertures maybe in fluid communication with a gas channel separate from a second gaschannel in fluid communication with the plurality of first plate slots.The plurality of slots may be generally arcuate in shape. The pluralityof slots may extend less than 50 percent of a circular distance of theshowerhead body. A gas in the first plate slots may not contact a gas inthe second plate slots until both of the gasses have traveled completelythrough the slots.

In another aspect, a semiconductor tool includes a reaction chamberdefining a processing area, a workpiece support within the reactionchamber, a showerhead for distributing at least one processing gaswithin the processing area, and a processing valve manifold in fluidcommunication with the showerhead to control the at least one processinggas flow into the showerhead, wherein the showerhead further includes afirst plurality of arcuate slots and a second plurality of arcuateslots, each of the plurality of arcuate slots having a common exit planeabove a workpiece support and the first plurality of arcuate slots beingconcentrically aligned with the second plurality of arcuate slots.

In an implementation, the at least one process gas flows radiallyoutward after leaving the first and second plurality of arcuate slots.Each ring of the plurality of first and second arcuate slots may bealternatively offset from adjacent rings of first and second arcuateslots. The semiconductor tool may include a vacuum port in fluidcommunication with the first plurality of arcuate slots and anothervacuum port in fluid communication with the second plurality of arcuateslots. The semiconductor tool may further include a purge port in fluidcommunication with the first plurality of arcuate slots and anotherpurge port in fluid communication with the second plurality of arcuateslots. The purge ports may be positioned radially outward of theplurality of first and second arcuate slots.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-sectional view of a reaction chamber with asusceptor in the wafer loading position.

FIG. 2 illustrates a top perspective view of a base member of theshowerhead.

FIG. 3 illustrates a bottom perspective view of the base member of theshowerhead.

FIG. 4 illustrates a top perspective view of a middle plate member ofthe showerhead.

FIG. 5 illustrates a bottom perspective view of the middle plate memberof the showerhead.

FIG. 6 illustrates a top perspective view of an upper plate member ofthe showerhead.

FIG. 7 illustrates a bottom perspective view of the upper plate memberof the showerhead.

FIG. 8 illustrates an enlarged view of the cross-sectional view seen inFIG. 1.

FIG. 9 illustrates a further enlarged view of the cross-sectional viewseen in FIG. 8 and labeled as FIG. 9.

FIG. 10 illustrates an enlarged view of the section labeled FIG. 10 inFIG. 9.

FIG. 11 illustrates a partial bottom view of the showerhead assembly.

FIG. 12 illustrates an enlarged view of the section labeled FIG. 12 inFIG. 11.

FIG. 13 illustrates an enlarged view of a cross-sectional view of ashowerhead having a plurality of ports positioned near a periphery ofthe showerhead.

FIG. 14 illustrates an enlarged view of a cross-sectional view of ashowerhead having a plurality of ports positioned near a periphery ofthe showerhead and a connection between the plurality of ports and avacuum exhaust line.

DETAILED DESCRIPTION

The present aspects and implementations may be described in terms offunctional block components and various processing steps. Suchfunctional blocks may be realized by any number of hardware or softwarecomponents configured to perform the specified functions and achieve thevarious results. For example, the present aspects may employ varioussensors, detectors, flow control devices, heaters, and the like, whichmay carry out a variety of functions. In addition, the present aspectsand implementations may be practiced in conjunction with any number ofprocessing methods, and the apparatus and systems described may employany number of processing methods, and the apparatus and systemsdescribed are merely examples of applications of the invention.

FIG. 1 illustrates a reaction chamber 20 having an upper chamber 22 anda lower chamber 24. Upper chamber 22 includes a showerhead 26, whilelower chamber 24 generally includes a susceptor assembly 28 as may becommonly known in the art which is moveable in the direction associatedwith arrows 30 to receive wafers (not shown) for loading, unloading, andprocessing. While the present disclosure illustrates and describesshowerhead 26 in a split chamber with upper and lower sections, it iswithin the spirit and scope of the present disclosure to incorporateshowerhead 26 in a non-split chamber reactor.

Showerhead 26 includes an upper plate 32, a middle plate 34, and a baseplate 36. Upper plate 32 includes a plurality of cooling fins 38extending vertically therefrom and a raised central portion 40 having aplurality of upper plate second gas holes 42 which may be oriented at anangle. In one implementation, the plurality of upper plate second gasholes 42 may be at least three gas holes, while in anotherimplementation there may be six or more gas holes, although any suitablenumber of gas holes may be incorporated. Further, an upper plate firstgas hole 44 may extend vertically through the raised central portion 40and into a first gas cavity 46 defined by and positioned between theupper plate 32 and the middle plate 34. Similarly, upper plate secondgas holes 42 extend through conduits 48 in the upper plate 32 andspecifically channels 50 in conduits 48 to reach a second gas cavity 52defined by and positioned between the middle plate 34 and the base plate36. The channels 50 may also extend through middle plate 34 beforeentering second gas cavity 52.

A gas control valve assembly 54 may be positioned on showerhead 26 andparticularly on raised central portion 40 with an inner o-ring 56 and anouter o-ring 58 preventing comingling of the gases during delivery andalso preventing the gases from leaking at the intersection between thegas control valve assembly 54 and the raised central portion 40. Gascontrol valve assembly 54 also includes a valve assembly first gas hole60 and a plurality of valve assembly second gas holes 62. As can be seenin FIG. 1, any suitable number of valve assembly second gas holes 62 maybe utilized, however a similar number of channels 50 may be required totransport the gas beyond the first gas cavity 46 and into the second gascavity 52. Similarly, an o-ring 64 is used to separate and seal the areabetween upper plate 32 and middle plate 34, while an o-ring 66 is usedto separate and seal the area between middle plate 34 and base plate 36.In a still similar fashion, o-rings 68 are exemplary of each o-ringwhich is located where conduits 48 meet a top surface of showerheadmiddle plate 34 to both prevent the second gas from leaking into thefirst cavity and preventing the first gas from entering channels 50.Finally, as will be discussed in greater detail below, an exhaustchannel 72 is formed in base plate 36 and may be fully enclosed by thebase plate 36 or partially formed by the base plate 36. Exhaust channel72 is in fluid communication with a processing area 74 through exhaustgap 76. While the present disclosure and Figures illustrate conduits 48extending from upper showerhead plate 32, it is within the spirit andscope of the present disclosure to rearrange the orientation of theconduits so that the conduits extend vertically upwards from middleplate 34 and contact a bottom surface of upper plate 32, whereappropriate sealing mechanisms, such as o-rings, may be located.

FIGS. 2 and 3 illustrate a top and bottom perspective views,respectively, of base plate 36. Base plate 36 includes a top side 78 anda bottom side 80, with top side 78 having an opening 82 for receivingthe upper and middle plates 32 and 34 therein. A sealing surface 84 ispositioned radially outward of slots 86, both of which are positionedwithin opening 82. As can be seen in both FIGS. 2 and 3, slots 86 may begenerally arcuate in shape and progressively smaller radial dimensionsas the slots 86 move radially inward. In another implementation, slots86 are offset from one another such that slots 88 on the most outwardring are offset from adjacent slots 90 on the second most outward ring.This trend or orientation may continue radially inward such thatadjacent rings of slots 86 are offset from one another, but every otherring of slots 90 are parallel with one another and have slightly smallerradial dimensions due to the decrease in radius of base plate 36 of eachinward slot. For example, the inward most slot 90 may be shaped morelike a circle instead of a slot, or the inward most slot 90 may notextend to the complete center of base plate 36 in other implementations.

As discussed above, base plate 36 also includes at least a portion ofexhaust channel 72 and a portion of exhaust gap 76 is formed by thechannel 72 edge. A sidewall 92 includes an exhaust port 94 with mountingholes 96 for securing a vacuum or exhaust apparatus to remove unusedprecursor and carrier gasses from the chamber and the exhaust channel.

Referring now to FIGS. 4 and 5, where middle plate 34 is shown ingreater detail. Middle plate 34 also includes a top side 98 and a bottomside 100. A plurality of slots 102 are similar to slots 86 in base plate36 in that slots 102 are generally arcuate in shape with decreasingradial dimensions as the various rows of slots change from radiallyoutside to radially inside. Further, slots 102 are also positionedsimilar to slots 86 in that each adjacent slot rows are offset from oneanother, while every other slot row may be parallel or aligned with oneanother, having only slightly smaller radial dimensions due to thesmaller radius of the plate from outside to inside. Further, slots 102may also include smaller and smaller slots to the extent that the innermost slot 102 may be generally circular in shape. Regardless of theposition, slots 102 and 86 do not extend for more than 50 percent or 180degrees around the showerhead and may extend for only 90 degrees or lessin additional embodiments.

FIG. 4 also illustrates channels 50 extending from top side 98 throughto bottom side 100 and into second gas cavity 52 formed between aplurality of protrusions 104 on bottom side 100. Channels 50 may besurrounded by a recessed o-ring surface 110 arranged to receive o-ring68 for example. In one implementation, each corresponding channel 50 andconduit 48 include their own respective o-ring to ensure that the firstand second gases do not see or interact with each other until desired.

FIG. 5 more clearly illustrates protrusions 104 extending from bottomside 100 of middle plate 34 long enough to fit within slots 86 of baseplate 36. Specifically, when a sealing surface 106 includes an o-ringcavity 107 and the surface contacts sealing surface 84 of base plate 36,protrusions 104 are dimensioned to extend through slots 86 of base plate36. Even further, protrusions 104 preferably extend through slots 86such that a bottom surface 108 of protrusions 104 are flush or even witha bottom surface of slots 86 extending through base plate 36.Accordingly, the protrusions 104 and slots 102 therein terminateco-planar with slots 86 of base plate 36 such that gas flowing fromslots 102 and 86 are unable to comingle until they leave the showerheadassembly at the same distance from the wafer or work piece (not shown).

Once assembled, the area surrounding each of protrusions 104 and definedby a top surface of lower plate 36 assists to define second gas cavity52. Specifically, the second gas can flow through the upper plate secondgas holes 42 in the upper plate and into channels 50 before reachingsecond gas cavity 52. Second gas cavity 52 then permits the second gasto flow between an area defined by an outer surface 112 of protrusions104 and an inner surface of slots 86 due to the complimentary shape,design, and orientation of slots 86 and protrusions 104. Further, thefirst gas flows through slots 102, and therefore protrusions 104, untilreaching bottom surface 108 of protrusions 104. Accordingly, the firstand second gases can meet just below showerhead base plate 36 bottomside 80.

Referring now to FIGS. 6 and 7, upper plate 32 is shown in both a topperspective view and a bottom perspective view, respectively. Upperplate 32 includes a top side 113 and a bottom side 114. As previouslynoted, a plurality of cooling fins 38 may be disposed throughout topside 113 to better control heating and gas flow rates to prevent gasesfrom decomposing within the showerhead. Raised central portion 40 alsoincludes an o-ring cavity 118 for receiving o-ring 58, while an o-ringcavity 120 is used to secure o-ring 56 when the gas control valve 54 ispositioned on raised central portion 40.

Bottom side 114 of upper plate 32 includes conduits 48 with channels 50as discussed above. The conduits 48 extend from a gas cavity surface 122which assists in providing a partial barrier of gas cavity 46.Specifically, gas cavity surface 122 forms the top and side walls forgas cavity 46 and receives a first gas flow from upper plate first gashole 44. Further, conduits 48 also act as a boundary for gas cavity 46since they are sealed off from the cavity and convey a second gasthrough channels 50. Bottom side 114 also includes a sealing surface 124having an o-ring cavity 126 formed therein. When assembled, sealingsurface 124 contacts top side 98 of middle plate 34 and o-ring 64 ispositioned within o-ring cavity 126 to seal the gas cavity 46 from thesecond gas cavity 52. While the present disclosure and illustrationsprovide one example of showerhead 26, a person of ordinary skill in theart will immediately recognize that a number of modifications may bemade without departing from the spirit and scope of the presentdisclosure. For example and without limitation, the showerhead shape maybe other than round, may include straight upper plate second holes 42instead of angled holes and the size of the various holes, channels, andfins may be modified to fit the reactor application. Process gases canenter either volume as shown or even from outer perimeter feed tubesand/or purge channels as will be discussed in greater detail below.

Referring now to FIG. 8, which is an enlarged view of a portion ofassembled showerhead 26 within reaction chamber 20, gas cavity 46 isformed in part by gas cavity surface 122 of bottom side 116 of upperplate 32, conduits 48, and top side 98 of middle plate 34. Gas cavitysurface 122 is shown generally angled from upward from a radiallyoutward position to a radially inward position, while top side 98 ofmiddle plate 34 is shown as generally flat. In another implementation,gas cavity surface 122 may be generally flat and top side 98 may beangled in either direction, still further, both top surface 98 and gascavity surface 122 may both be flat or tapered in opposite directions asmay be appropriate for individual applications.

In a similar fashion, second gas cavity 52 is generally defined bybottom side 100 of middle plate 34, protrusion outer surfaces 112, andtop side 78 of base plate 36. As shown, bottom side 100 of middle plate34 may be generally flat, with top side 78 being angled downward from aradially outward position to a radially inward position. In anotherimplementation, top side 78 may be flat, while bottom side 100 may beangled. In still another implementation, both top side 78 and bottomside 100 may both be flat or both be angled in the same or differentdirections without departing from the spirit and scope of thedisclosure. The shape, size, and thickness of each gas cavity 46 and 52may be angled or dimensioned to provide better flow characteristics aswell as limiting pocket formation which may increase purge times.

Gas flow for the first gas may generally travel in the directionassociated with arrows 128 through upper plate first gas hole 44, intogas cavity 46 and through slots 102 in protrusions 104. Gas flow for thesecond gas may generally travel in the direction associated with arrows130 through upper plate second gas hole 42, into channels 50, followedby second gas cavity 52 before exiting between protrusion outer surface112 and slots 86.

FIG. 9 illustrates an enlarged view of a portion of showerhead 26 andspecifically shows protrusions 104 with slots 102 therein positionedwithin slots 86 of base plate 36. While the operation and arrangement ofthe showerhead remains the same, it will be appreciated that slots 102may extend approximately two-thirds of the distance from top side 98 toprotrusion bottom surface 108 at a first radius before a second,smaller, radius is reached in slots 102. A shoulder 132 may mark thetransition from the first radius to the second radius, which may beadvantageous for gas flow characteristics both during processing andpurging operations. In another implementation, shoulder 132 can be flatas shown or angled inwards to assist the flow of gas from 128 into thevarious slots 102 before contacting angled side wall 134.

FIG. 10 is an even greater magnification of the showerhead.Specifically, shoulder 132 can be seen in greater detail, as well as thevarious components from the first radius above the shoulder to a smallerradius below shoulder 132. It should be appreciated that theincorporation of shoulder 132 and varying/different radii within slots102 are merely examples of various configurations which may be utilizedand are not intended to in anyway limit the disclosure. Protrusions 104may include an angled side wall 134 to provide an even flow of the gasfrom slot 102 as it exits the protrusion. As can also be seen, a gap isformed between protrusion outer surface 112 and slots 86 which is usedto convey the second gas into the reaction chamber. In oneimplementation, the gap G between protrusion outer surface 112 and slots86 is between 0.575 mm and 0.800 mm, while the gap S in slots 102 isbetween 0.636 mm and 1.100 mm. In another implementation, the gap G mayvary between 0.100 mm and 2 mm and the gap S may vary between 0.100 mmand 2 mm. In still another implementation, the gaps G and S may varyfrom radial positions such that gaps G and S increase or decrease fromradially inward to radially outward positions or from radially outwardto radially inward positions.

FIGS. 11 and 12 illustrate enlarged bottom views of the assembledshowerhead 26 showing the gaps G and S. Further, arrows 136 illustratethe directional movement of gas flow after exiting gaps G and S.Specifically, both gases flow radially outward after passing protrusionbottom surface 108. Advantageously, the plurality of overlapping rows ofslots 86 and 102 provide a uniform stream of gas in a generally radialdirection. The overlapping nature helps to assure that terminating areas138 of a particular slot 86 and 102 still see gas from the radiallyinward adjacent row. Accordingly, a more uniform gas flow is achievedsince there is overlap at each terminating area 138.

FIG. 13 illustrates a second aspect showerhead 140 having componentsgenerally similar to showerhead 26. Upper plate 32 includes secondarygas lines 142 extending from gas cavity surface 122 through top side114. In one implementation, there may be six or more secondary gas lines142 positioned near the periphery of gas cavity surface 122, althoughany number of secondary gas lines 142 may be utilized, including withoutlimitation, 1, 2, 3, 4, 5, or more than 6. Secondary gas lines 142 mayfeed by a plenum 144 or a plurality of single plenums at each secondarygas line 142, where an inner o-ring 146 and an outer o-ring 147 are usedto seal a cap 148. A valve 150 is positioned on cap 148 and may beextend through cap 148. A hole 149 may be located within cap 148 toallow valve 150 to communicate with plenum 144. A valve gas line 152 isalso connected to valve 152 and in fluid communication with plenum 144through valve 150. While only a single valve 150 is shown for plenum144, any suitable number of valves may be utilized, and in oneimplementation there are as many valves as there as secondary gas lines142.

A plurality of secondary gas lines 154 may be included in base plate 36which are in fluid communication with a plenum 156 or a plurality ofplenums as applicable. An inner o-ring 151 and an outer o-ring 153 mayonce again seal plenum 156 and caps 148 together while a valve or valves150 are positioned on caps 148. A hole 155 may be positioned in cap 148so that valve 150 can communicate with plenum 156. Still further, valvegas lines 152 are once again connected to all valves 150 in thisimplementation. Similar to the valves for upper plate 32, valves in baseplate 36 may also be any suitable number, the number of plenums mayvary, and the number of secondary gas lines may vary without departingfrom the spirit and scope of the disclosure.

In operation, valves 150 operate to provide a positive pressure to flowa carrier gas during purging steps or a negative pressure to withdrawgas from the showerhead gas cavities (46 and 52) respectively. Forexample, in one implementation, valves 150 of upper plate 32 may providea purge gas flow of carrier gas, while valves 150 of base plate 36 mayprovide a vacuum to remove unused precursor remaining within theshowerhead second gas cavity. In the same manner, the roles may bereversed so that valves 150 of upper plate 32 provide a vacuum, whilevalves 150 of base plate 36 provide a purge gas. In still anotherimplementation, valves 150 may provide a purge gas flow in both theupper plate 32 and the base plate 36 or valves 150 may provide a vacuumin both the upper plate 32 and the base plate 36. A person of ordinaryskill in the art will immediately appreciate that a number of operationsmay be utilized from the same valve configurations without departingfrom the spirit and scope of the disclosure. It may also be that thevacuum or purge is pulsed during different steps, for example, in an ALDprocess where the valves are open during purge steps to assist inremoval of precursor from volumes after precursor(s) pulses.

FIG. 14 illustrates a third aspect showerhead 158 which is similar toshowerhead 140 in that both showerheads utilize valves 150 for providinga purge gas or a vacuum as the application may require. Severaldifferent features include an inner o-ring 160 and an outer o-ring 161surrounding an exhaust feed line 163 adjacent cap 148 and a plenum line162 connecting plenum 156 and valve 150. Specifically, exhaust feed line163 connects valve 150 and secondary gas line 154 such that imparting avacuum on valve 150 removes unused precursor in second gas cavity 52 anddumps the unused precursor directly into exhaust channel 72. Valve 150in upper plate 32 may operate in a similar fashion to provide a vacuumwhich may or may not lead to exhaust channel 72 or may provide a purgegas of an inert gas to assist with the purging operation. The variousarrangements, orientations, modifications, and procedures discussedabove for showerhead 140 may be incorporated into showerhead 158 withoutdeparting from the spirit and scope of the present disclosure.Accordingly, it is seen that a number of changes may be made to assistwith decreasing resonance time and increasing the purge efficiency.

The above described showerhead and gas delivery system may be utilizedin a number of processing applications, including chemical vapordeposition (CVD) and Atomic Layer Deposition (ALD) or a combinationthereof. One particularly useful application is depositing transitionmetal carbides, borides, and silicides using transition metal halidesand either a metal organic compound or a silicon/boron hydride. Further,positive results can also be obtained by using transition metal halideswith a metal organic compound and a silicon or boron hydride. Alsonanolaminates of pure metal and metal nitrids or carbides can bedeposited. Examples of suitable metal organic compounds include, but arenot limited to, trimethylaluminium (TMA), triethylaluminium (TEA),triethylborane (TEB), dimethylaluminum hydride (DMAH), dimethylethylamine alane (DMEAA), amine aluminaborane (TMAAB) and relatedchemistries. Examples of suitable silicon and boron hydrides include,but are not limited to, silylene (SiH₂), disilane (Si₂H₆), trisilane(S₃H₈), diborane (B₂H₆), and related chemistries.

In operation, metal organic compounds tend to more easily decompose inthe presence of transition metal halides. Accordingly, it isadvantageous to deposit transition metal carbides, which may includesilicon or boron elements, through a gas separated showerhead to avoidany residual chlorine in the showerhead causing decomposition of theorganic compound well before reaching a wafer surface. Decomposition ofthis nature can lead to particle formation and increased build-up whichmay shed film and also create unwanted particles within the chamber.

Advantageously, showerheads 26 may include separated gas cavities 46 and52 for example, with first gas cavity 46 being distal to the wafer orprocessing area 74 and therefore being generally cooler than second gascavity 52 which is located proximate and even adjacent the waferprocessing area 74. Further, first gas cavity 46 may include coolingfins 38 which further help to control and/or reduce the temperaturewithin first gas cavity 46 with respect to second gas cavity 52. Eventhough first gas cavity 46 is in fluid communication with processingarea 74, spacing first gas cavity 46 from the processing area allows theprecursor within the first gas cavity to be more stable duringprocessing. In this arrangement, it is advantageous to locate metalorganic chemistries in the first gas cavity 46 and locate transitionmetal halides in the second gas cavity 52, thereby positioning thetransition metal halide gas cavity between the processing area and themetal organic source cavity in the showerhead 26. Thus, the metalorganic sources are positioned further away from the transition metalhalide sources when both the metal organic and the transition metalhalide sources are within the showerhead 26.

Alternatively, a silicon or boron hydride may replace the transitionmetal halide in the second gas cavity and operate in a similar fashionto function as an insulator for the metal organic precursor or source inthe first gas cavity. Thus, it is advantageous to locate the lessthermally stable precursor in a showerhead gas cavity that is distal theprocessing area, while locating the more thermally stable precursor in ashowerhead gas cavity that is proximate the processing area. While thedescription of various metal organic sources, transition metal halidesources, and silicon/boron hydrides has been demonstrated in showerhead26, it is suitable to use any gas separated showerhead so long as thesources do not interact with one another until after exiting theshowerhead and the relative positions of the sources in the showerheadare utilized.

These and other embodiments for methods and apparatus for a reactionchamber with a showerhead having multiple gas outlets concentricallypositioned and having an arcuate shape therein may incorporate concepts,embodiments, and configurations as described with respect to embodimentsof apparatus for measuring devices described above. The particularimplementations shown and described are illustrative of the inventionand its best mode and are not intended to otherwise limit the scope ofthe aspects and implementations in any way. Indeed, for the sake ofbrevity, conventional manufacturing, connection, preparation, and otherfunctional aspects of the system may not be described in detail.Furthermore, any connecting lines shown in the various figures areintended to represent exemplary functional relationships and/or physicalcouplings between the various elements. Many alternative or additionalfunctional relationship or physical connections may be present in thepractical system, and/or may be absent in some embodiments. Further,various aspects and implementations of other designs may be incorporatedwithin the scope of the disclosure.

As used herein, the terms “comprises”, “comprising”, or any variationthereof, are intended to reference a non-exclusive inclusion, such thata process, method, article, composition or apparatus that comprises alist of elements does not include only those elements recited, but mayalso include other elements not expressly listed or inherent to suchprocess, method, article, composition or apparatus. Other combinationsand/or modifications of the above-described structures, arrangements,applications, proportions, elements, materials or components used in thepractice of the present invention, in addition to those not specificallyrecited, may be varied or otherwise particularly adapted to specificenvironments, manufacturing specifications, design parameters or otheroperating requirements without departing from the general principles ofthe same.

What is claimed is:
 1. A semiconductor tool comprising: a reactionchamber defining a processing area; a workpiece support within thereaction chamber; a showerhead for distributing at least one processinggas within the processing area; and, a processing valve manifold influid communication with the showerhead to control the at least oneprocessing gas flow into the shower head; wherein the showerhead furthercomprises a first plurality of arcuate slots and a second plurality ofarcuate slots, each of the plurality of arcuate slots having a commonexit plane above a workpiece support and the first plurality of arcuateslots being concentrically aligned with the second plurality of arcuateslots.
 2. The semiconductor tool of claim 1 wherein the at least oneprocess gas flows radially outward after leaving the first and secondplurality of arcuate slots.
 3. The semiconductor tool of claim 1 whereineach ring of the plurality of first and second arcuate slots arealternatively offset from adjacent rings of first and second arcuateslots.
 4. The semiconductor tool of claim 1 further comprising a vacuumport in fluid communication with the first plurality of arcuate slotsand another vacuum port in fluid communication with the second pluralityof arcuate slots.
 5. The semiconductor tool of claim 1 furthercomprising a purge port in fluid communication with the first pluralityof arcuate slots and another purge port in fluid communication with thesecond plurality of arcuate slots.
 6. The semiconductor tool of claim 5wherein the purge ports are positioned radially outward of the pluralityof first and second arcuate slots.